1. Field of the Invention
The present invention relates to powered toothbrushes, and more particularly, to a powered toothbrush having a curved neck of a constant curvature and a curved flexible shaft.
2. Discussion of Related Art
Toothbrushes provide many oral hygiene benefits. For example, toothbrushes remove plaque and food debris to help avoid tooth decay and disease. They remove stained pellicle from the surface of each tooth to help whiten the teeth. Also, the bristles combined with the brushing motion massage the gingival tissue for stimulation and increased health of the tissue.
Powered toothbrushes have been available for some time. Powered toothbrushes have advantages over manual (non-powered) toothbrushes in that they impart movement to the bristles at much higher speeds than possible manually. They also may impart different types and directions of motion. These motions, generally in combination with manual movement of the toothbrush by a user, provide superior cleaning than manual toothbrushes. Typically, powered toothbrushes are powered by disposable or rechargeable batteries that power an electric motor that in turn drives a toothbrush head.
Known powered toothbrushes include a brush head with a bristle carrier portion that rotates, oscillates or vibrates in some manner so as to clean the teeth. The bristles, which typically comprise bristle tufts, are generally uniform with one end fixed into the bristle carrier portion and the other end free to contact the surface of the teeth while brushing. The free ends of the various tufts present a surface envelope that is capable of some deformation when the bristles bend. When in contact with the surface to be brushed, the bristles may deform so that the surface envelope tends to conform to the complex surface of the teeth. Human teeth generally lie in a “C” shaped curve within the upper and lower jaw bones, and each row of teeth consequently has a convex outer curve and a concave inner curve. Individual teeth often have extremely complex surfaces, with areas that may be flat, concave or convex. The more precise the contact between the bristles and the tooth surface, the more effective the toothbrush may be in cleaning, whitening and/or stimulating.
Although powered toothbrushes such as those described immediately above provide advantages over manual toothbrushes, they are not designed for engaging teeth in hard to reach areas of the mouth. Further, the shafts of such powered toothbrushes are not designed to allow for efficient contact between the bristles and the tooth surface. Additionally, such powered toothbrushes utilize multiple, segmented drive shafts coupled to gears, which complicate the powered toothbrush and increase the failure rate.